Bartonella Species - Bartonellosis

Bartonella spp cause several different diseases, including cat-scratch disease (CSD). Serology can confirm the diagnosis; culture is generally not recommended because of low sensitivity. PCR testing of blood, tissue, or CSF may also be helpful.

Diagnosis

Indications for Testing

High level of suspicion based on symptoms and exposure risk

Laboratory Testing

  • CDC Bartonella diagnosis and treatment information for healthcare providers (2015)
  • Bartonella henselae
    • Nonspecific testing
      • CBC – mildly elevated white blood cell count and elevated or diminished platelets
    • Acute and convalescent serum specimens for antibody testing
      • 70-90% positive in immunocompetent patients
      • Best evidence of infection is significant change on two appropriately timed specimens (both tests performed in same laboratory at same time)
      • Confirmation requires a four-fold change in titers between acute and convalescent specimens
      • Low-positive IgG – suggests past exposure or infection
      • High-positive IgG – may indicate current or recent infection (not conclusive)
    • Polymerase chain reaction (PCR) from whole blood, tissue, or cerebrospinal fluid (CSF)
      • Rapid test
      • Relatively sensitive, very specific
    • Culture of involved nodes
      • Difficult
      • Long incubation periods with poor yield
      • Not recommended – sensitivity very low
  • Bartonella quintana
    • Trench fever – may require culture, PCR, or serology
    • Endocarditis – blood cultures may be negative

Histology

  • Warthin-Starry silver stain
    • B. henselae – pathologic examination of involved nodes
    • B. quintana – diagnosis of bacillary angiomatosis based on histopathologic findings of angiomas associated with tiny clumps of bacilli

Differential Diagnosis

Background

Epidemiology

  • B. henselae
    • Incidence – 22,000 infections annually in the U.S. (~9/100,000)
    • Age – children <1 year have the greatest rate of infection
    • Occurrence – most common in warm, humid climates during autumn and winter months
    • Transmission – usually by cats to humans (fleas mainly transmit the disease directly through a cat scratch; flea-borne transmission to humans may also occur)
      • Most affected patients do not recall being scratched by a cat
  • B. quintana
    • Incidence – generally low; however, increasing prevalence in homeless populations in U.S. and Europe
    • Transmission – body louse (Pediculus humanus corporis)

Organism

  • Genus Bartonella contains aerobic, fastidious, gram-negative bacillus
  • Associated with four primary clinical syndromes
    • CSD – B. henselae, B. clarridgeiae
    • Bacillary angiomatosis – B. quintana, B. henselae
    • Bacillary peliosis hepatitis – B. henselae
    • Relapsing fever with bacteremia (trench fever) – B. quintana

Risk Factors

  • B. henselae
    • Cats with fleas – ~60% of strays and 40% of domestic cats are bacteremic for B. henselae
    • Rough play with cats – especially kittens
    • Unwashed bites and scratches from cats or allowing cats to lick open wounds
  • B. quintana
    • Immunocompromised persons – especially those with HIV
    • Homelessness
    • Alcoholism

Clinical Presentation

  • B. henselae
    • Immunocompetent host
      • Common presentations – CSD
        • Localized papule progressing to a pustule develops 3-5 days after cat scratch
          • Initial lesion heals uneventfully
        • Tender, unilateral regional lymphadenopathy develops 1-2 weeks later – 90% of cases
          • Generally persists for 2 weeks to 3 months before resolving spontaneously
          • Cervical and axillary – most common
          • Secondary bacterial superinfection of involved nodes – ~10% of cases
      • Other manifestations
        • Neurologic – encephalopathy, transverse myelitis, radiculitis, cerebellar ataxia
        • Hepatitis
        • Osteomyelitis
        • Disseminated infection (endocarditis) – associated with mortality
        • May also present as granulomatous disease
        • Ophthalmic
          • Conjunctival inoculation may cause Parinaud oculoglandular syndrome with conjunctivitis and periauricular lymphadenopathy
          • ​Neuroretinitis
    • Immunocompromised host
      • Bacillary angiomatosis
        • Nontender, firm, red-purple colored skin lesions
          • Dissemination to organs – pseudoneoplastic vasculitis proliferation
          • Potentially fatal if not treated
      • Bacillary peliosis
        • Vasoproliferation within the liver and spleen
          • Blood-filled cysts with possible organisms in the cysts
  • B. quintana
    • Trench fever
      • Sudden onset headache, meningitis, and relapsing fever
      • Relapsing fever with bacteremia
        • Relapses common when short-course antibiotics are used
      • May cause endocarditis
      • No fatalities reported
    • Bacillary angiomatosis
      • Most common in immunocompromised patients (eg, HIV)
      • Many organs may be affected –  bone marrow, lymph nodes, liver, spleen
      • Hallmark symptoms – vascular nodules, papules, or tumors with proliferation of new blood vessels (angiogenesis)
      • Lesions, termed epithelioid angiomatosis, resemble Kaposi sarcoma

ARUP Lab Tests

Primary Tests

May confirm a current or past exposure to B. henselae or B. quintana in patient with typical signs and symptoms and a compatible exposure history

If test results are equivocal, repeat testing in 10-14 days

Detect Bartonella spp in blood, cerebrospinal fluid (CSF), or tissue

Detect presence of bacteria in blood

Use in patients with endocarditis to detect if Bartonella spp are etiology

Limited to the University of Utah Health Sciences Center only

Related Tests

Order to differentiate between bacterial and viral etiology

Diagnose cat-scratch disease in patient with typical signs and symptoms and a compatible exposure history

Confirm suspected Trench fever in patient with typical signs and symptoms and compatible exposure history

Confirm a current or past B. henselae infection

Confirm an early or recent B. henselae infection

Confirm suspected Trench fever in patient with typical signs and symptoms and compatible exposure history

Confirm suspected Trench fever in patient with typical signs and symptoms and compatible exposure history

Medical Experts

Contributor

Couturier

Marc Roger Couturier, PhD, D(ABMM)
Associate Professor of Clinical Pathology, University of Utah
Medical Director, Parasitology/Fecal Testing, Infectious Disease Antigen Testing, Bacteriology, and Molecular Amplified Detection, ARUP Laboratories
Contributor

Fisher

Mark A. Fisher, PhD, D(ABMM)
Associate Professor of Clinical Pathology, University of Utah
Medical Director, Bacteriology, Special Microbiology, and Antimicrobial Susceptibility Testing, ARUP Laboratories
Contributor

References

Additional Resources
Resources from the ARUP Institute for Clinical and Experimental Pathology®